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Linmei Nie

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Papers by Linmei Nie

The migration and accumulation of typical pollutants in the growing media layer of bioretention facilities

Environmental Science and Pollution Research

A series of complex physical and chemical processes, such as interception, migration, accumulatio... more A series of complex physical and chemical processes, such as interception, migration, accumulation, and transformation, can occur when pollutants in stormwater runoff enter the growing media layer of bioretention facilities, affecting the purification of stormwater runoff by bioretention facilities. The migration and accumulation of pollutants in the growing media layer need long-term monitoring in traditional experimental studies. In this study, we established the Hydrus-1D model of water and solution transport for the bioretention facilities. By analyzing the variation of cumulative fluxes of NO 3-N and Pb with time and depth, we investigated pollutant migration and accumulation trends in the growing media layer of bioretention facilities. It can provide support for reducing runoff pollutants in bioretention facilities. The Hydrus-1D model was calibrated and verified with experimental data, and the input data (runoff pollutant concentration) for the pollutant concentration boundary was obtained from the SWMM model. The results demonstrated that the cumulative fluxes of NO 3-N and Pb increased with the passage of simulation time and depth of the growing media layer overall. From the top to the bottom of the growing media layer, the change rates of the peak cumulative fluxes of NO 3

Flomrisiko og konsekvensanalyse : Pilotprosjekt E18 ved Hoffsbekken

Rapporten inngår i en serie rapporter fra FoUprosjektet “Klima og transport”, etatsprosjekt 2007-... more Rapporten inngår i en serie rapporter fra FoUprosjektet “Klima og transport”, etatsprosjekt 2007-2010. Hensikten med prosjektet er å forbedre rutiner og regelverk for planlegging, prosjektering, bygging, drift og vedlikehold av vegnettet som svar på endrede klimaforhold. Rapporten tilhører delprosjekt 3 ”Flom og erosjonssikring” og inneholder en hydraulisk kapasitetsberegning for en kulvert i Oslo, under E18 ved Hoffsbekken. Effekten av klimaendring og urbanisering er beregnet og kulverten vurderes som flomutsatt. Kulvertens kapasitet er ikke stor nok til en 20 års flom i Hoffsbekken

Identification and analysis of most vulnerable infrastructure in respect to floods

This document reflects only the authors' views and not those of the European Community. This work... more This document reflects only the authors' views and not those of the European Community. This work may rely on data from sources external to the members of the FloodProBE project Consortium. Members of the Consortium do not accept liability for loss or damage suffered by any third party as a result of errors or inaccuracies in such data. The information in this document is provided "as is" and no guarantee or warranty is given that the information is fit for any particular purpose. The user thereof uses the information at its sole risk and neither the European Community nor any member of the FloodProBE Consortium is liable for any use that may be made of the information.

Different hydrodynamic conditions on the deposition of organic carbon in sediment of two reservoirs

Hydrobiologia, 2015

In regulated freshwater ecosystems, the deposition process of organic carbon (OC) in sediment cou... more In regulated freshwater ecosystems, the deposition process of organic carbon (OC) in sediment could be affected by all the changes of physical, chemical, and biological factors. To assess different hydrodynamic conditions on the deposition of OC in sediment, the combination of elemental and stable isotope analyses was carried out in two reservoirs: the Huairou Reservoir (HR), which undergoes seasonal water level fluctuation (WLF) like natural lakes, and the Shisanling Reservoir (SR), which undergoes daily WLF for the operation of pumped storage power station. In general, OC concentration and its variation were comparable in the two reservoirs, whereas the OC distribution showed completely different features. The OC burial rate in SR was nearly two times more than in the HR, which reflect the impact of WLFs on the erosion of soil. For the relative contribution of phytoplankton-derived OC (P-OC), macrophytederived OC (M-OC), and terrestrial OC (T-OC) in sediment, the T-OC and M-OC in the SR were both higher than those of the HR, whereas the P-OC was markedly lower. Furthermore, the classification of nearshore and offshore sediments suggested that hydrodynamic conditions affected the T-OC import by physical processes and the in situ contributions of P-OC and M-OC with a spatial difference.

Sustainable water resources management in Tianjing, China

Sustainable Water Management Solutions for Large Cities: The Proceedings of the International Symposium on Sustainable Water Management for Large Cities (S2): Held During the Seventh Scientific Assembly of the International Association of Hydrological Sciences (IAHS) at Foz Do Iguaçu, Brazil, 3-9..., 2005

Tianjing is one of the largest cities in China. This paper provides an overview of its progress i... more Tianjing is one of the largest cities in China. This paper provides an overview of its progress in sustainable water resources management. Waterrelated problems, such as drought and flood, water pollution, deterioration of water-related ecosystem and environment, are addressed. Among them, the water shortage problem associated with the city's development is highlighted. The city's sustainable water resources development plan for the early 21st century is introduced, and the measures are described. Future ...

Editorial: Assessment and adaptation to climate change impacts in cold regions

Journal of Water and Climate Change, 2021

Evaluation of the Climate Forecast System Reanalysis Weather Data for Watershed Modeling in Upper Awash Basin, Ethiopia

Water, 2018

Availability of reliable meteorological data for watershed modeling is one of the considerable ch... more Availability of reliable meteorological data for watershed modeling is one of the considerable challenges in the Awash River Basin in Ethiopia. To overcome this challenge, the Climate Forecast System Reanalysis (CFSR) global weather data was evaluated and compared with the limited conventional weather data available in the Upper Awash Basin. The main objective of this study was to search for an optional data source for hydrological modeling, instead of using the limited available data, and for data-scarce areas of the basin. The Soil and Water Assessment Tool model was used to compare the performance of the two weather datasets at simulating monthly streamflow. For calibration, validation, and uncertainty analysis, the sequential uncertainty fitting algorithm was used. The model evaluation statistics showed that the CFSR global weather data performed similarly to the conventional weather data for simulating the observed streamflow at Melka Kunture. At Keleta, where the conventional data is scarce, the CFSR performed better. The CFSR performance at the two sub-basins indicated that it performed better for the large sub-basin, Melka Kunture. Generally, the CFSR weather data are a good addition to the dataset for areas where no reliable weather data exists for hydrological modeling in the basin. The precipitation data of the CFSR are slightly higher than that of the conventional data, which also resulted in a relatively higher water balance components.

Flomfrekvensanalyse og flomvannlinjeberegninger for byvassdrag

Utbygging og klimaendring gir raskere og større avrenning på overflater og deretter til vassdrag.... more Utbygging og klimaendring gir raskere og større avrenning på overflater og deretter til vassdrag. Dette øker flomrisikoen i vassdrag spesielt i byer. NVEs retningslinjer for planlegging og utbygging langs vassdrag forutsetter at det ikke bygges lavere enn vannivået ved 200 års flom. Denne artikkelen introduserer metoder og verktøy for å utføre flom- og flomvannlinjeberegninger i byvassdrag og hvordan dette kan gjennomføres. Flom og flomvannlinjeberegninger for Høylandsåna og Storånavassdraget i Sandnes kommune er brukt som eksempel. Det er også et mål at flom- og flomvannlinjeberegningene skal gi et grunnlag for forebyggende tiltak og til å legge inn hensynssoner langs vassdraget i forslag til ny kommunepla

China’s Sponge City Construction: Ambition and challenges

China’s Sponge City Construction (SCC) initia ted by the central government, represents an enorm... more China’s Sponge City Construction (SCC) initia ted by the central government, represents an enormous efforts and unprecedented under taking by the government for achieving urban sustainability, which presents also a global chal lenge and demand for urban planners united with implementation of natural based solutions to reduce urban flooding, water shortage and serious pollution of water courses and water bodies during urbanization and climate change. Sponge city construction aims to achieve an integrated and sustainable management of urban stormwater through its 6step approaches, i.e. Infiltration, Detention, Storage, Cleaning, Reuse and Discharge. 30 Chinese cities were selected as pilot cities, received financial support from the central government to implement of diffe rent LID solutions. This paper introduced the SCC concept, bringing together the political objectives, technical approach, guidelines, finan cial scheme, pilot projects, successful expereince, and challenges d...

Factors affecting the permeability of the growing media used in bioretention systems

Journal of Hydrology

Urban Flood Modeling of a Partially Separated and Combined Drainage System in the Grefsen Basin in Oslo, Norway

Journal of Water Management Modeling, 2022

The Storm Water Management Model (SWMM) has been globally used for stormwater management. However... more The Storm Water Management Model (SWMM) has been globally used for stormwater management. However, the calibration and evaluation of SWMM for historical rainfall–runoff events in partially separated and combined drainage systems is rarely reported in Norway. In this study, we employed SWMM for the Grefsen catchment in Oslo, Norway. The main problem in the Grefsen basin is combined sewer overflow. We calibrated the model parameters based on 32 rainfall–runoff events and evaluated the calibrations using four indicators: Nash–Sutcliffe efficiency, percentage bias, and continuity errors for runoff and flow. There were 32 successful calibrations using Nash–Sutcliffe efficiency, 30 successful calibrations using percentage bias, 32 successful calibrations using continuity error runoff, and four successful calibrations using continuity error flow. SWMM can well simulate the dynamics of hydrological and hydraulic systems in this catchment. Among the 124 validations, there were 88 successful ...

Enrichment Evaluation of Heavy Metals from Stormwater Runoff to Soil and Shrubs in Bioretention Facilities

Water, 2022

Bioretention facilities with different inflow concentrations, growing media and plants were exami... more Bioretention facilities with different inflow concentrations, growing media and plants were examined to determine whether the soil in these facilities was polluted with heavy metals and whether runoff had obvious toxic effects on plants. Using Beijing soil background value as the standard, the soils were evaluated by bioaccumulation index and single factor index. The results show that stormwater runoff containing Cu caused slight pollution in soils, and stormwater runoff containing Zn and Pb was not polluted. Nemerow comprehensive index evaluation revealed that the heavy metals content in the facilities containing vermiculite (a yellow or brown mineral found as an alteration product of mica and other minerals, used for insulation or as a moisture-retentive medium for growing plants) and perlite (a form of obsidian characterized by spherulites formed by cracking of the volcanic glass during cooling, used as insulation or in plant growth media) were higher than the standard. High infl...

Factors affecting the ability of extensive green roofs to reduce nutrient pollutants in rainfall runoff

Science of The Total Environment, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Assessment of the impacts of landscape patterns on water quality in Trondheim rivers and Fjord, Norway

Water Supply

Due to the impacts of hydrological and ecological processes on water quality, discharges from ups... more Due to the impacts of hydrological and ecological processes on water quality, discharges from upstream catchments have induced significant pollution to the recipients. This study aims to investigate the possible pollution sources from catchments with different types of land use and landscape patterns and develop the relationships between water quality and the catchment hydro-geological and environmental variables. Data from 10 monitoring sites in Trondheim formulated the basis of the case study. Thermotolerant coliform bacteria (TCB) and total phosphorus (TP) were applied as main indicators to represent the water quality in the recipient rivers, streams and in Trondheim Fjord. Based on the GIS-oriented spatial analysis, 15 hydro-geographical and landscape parameters were selected as explanatory variables. Multiple linear regression (MLR) models were developed at catchment and river reach scales to study correlations between the explanatory variables and the response variables, TCB a...

A Review of Hydrological Models Applied in the Permafrost-Dominated Arctic Region

Geosciences, 2020

The Arctic region is the most sensitive region to climate change. Hydrological models are fundame... more The Arctic region is the most sensitive region to climate change. Hydrological models are fundamental tools for climate change impact assessment. However, due to the extreme weather conditions, specific hydrological process, and data acquisition challenges in the Arctic, it is crucial to select suitable hydrological model(s) for this region. In this paper, a comprehensive review and comparison of different models is conducted based on recently available studies. The functionality, limitations, and suitability of the potential hydrological models for the Arctic hydrological process are analyzed, including: (1) The surface hydrological models Topoflow, DMHS (deterministic modeling hydrological system), HBV (Hydrologiska Byråns Vattenbalansavdelning), SWAT (soil and water assessment tool), WaSiM (water balance simulation model), ECOMAG (ecological model for applied geophysics), and CRHM (cold regions hydrological model); and (2) the cryo-hydrogeological models ATS (arctic terrestrial s...

Quantifying the effects of watershed subdivision scale and spatial density of weather inputs on hydrological simulations in a Norwegian Arctic watershed

Journal of Water and Climate Change, 2021

The effects of watershed subdivisions on hydrological simulations have not been evaluated in Arct... more The effects of watershed subdivisions on hydrological simulations have not been evaluated in Arctic conditions yet. This study applied the Soil and Water Assessment Tool and the threshold drainage area (TDA) technique to evaluate the impacts of watershed subdivision on hydrological simulations at a 5,913-km2 Arctic watershed, Målselv. The watershed was discretized according to four TDA scheme scales including 200, 2,000, 5,000, and 10,000 ha. The impacts of different TDA schemes on hydrological simulations in water balance components, snowmelt runoff, and streamflow were investigated. The study revealed that the complexity of terrain and topographic attributes altered significantly in the coarse discretizations: (1) total stream length (−47.2 to −74.6%); (2) average stream slope (−68 to −83%); and (3) drainage density (−24.2 to −51.5%). The spatial density of weather grid integration reduced from −5 to −33.33% in the coarse schemes. The annual mean potential evapotranspiration, evap...

Sensitivity analysis of the SWAT model to spatial distribution of precipitation in streamflow simulation in an Arctic watershed

IOP Conference Series: Earth and Environmental Science, 2020

This study approached a physically based, semi-distributed SWAT model to test the model sensitivi... more This study approached a physically based, semi-distributed SWAT model to test the model sensitivity to the spatial distribution of precipitation. Ten scenarios of precipitation from five scattered rain gauges in an Arctic watershed Målselv in northern Norway were used as inputs to run the SWAT model. Streamflows were simulated. The model runs at monthly time interval based on the historical data of precipitation from 1979-2012. The study used statistical parameters, values of long-term average monthly streamflow and streamflow hydrograph between simulated and observed data for sensitivity analysis. The study found that the result of streamflow simulation is highly sensitive with spatial distribution of rain gauges input. For instance, the scenarios integrating rain gauge number 3, locating inside the watershed with lower precipitation amount than average of selected rain gauges, provided model unsatisfactory (statistical coefficient NSE < 0.5) in streamflow simulation. However, s...

Evaluating the Effects of Watershed Subdivision on Hydrological Simulation by Swat Model in an Arctic Watershed

IOP Conference Series: Earth and Environmental Science, 2020

The hydrological model SWAT is a state-of-the-art tool for environmental and water resources mana... more The hydrological model SWAT is a state-of-the-art tool for environmental and water resources management. Like other semi-distributed models, the whole river basin in the SWAT model is delineated into smaller sub-basins prior to conducting the simulation. Watershed delineation is an importance step since it could potentially influence the modelling results. The present study aimed to conducte an investigation of the effects of watershed delineation schemes on hydrological simulation in an Arctic watershed Målselv, north of Norway. Four delineation schemes were set up with different threshold drainage area (TDA) from fine to coarse including 100 ha, 2,000 ha, 5,000 ha and 10,000 ha. The model was run on monthly time step from 1979-2012. The results showed higher variation of average annual precipitation and runoff especially in the upstream sections of the watershed by the fine TDA schemes compared to the coarse ones. The average monthly precipitation and runoff slightly increased from the finest TDA scheme to the coarsest scheme. All TDA schemes reproduced the observed tendency of the average monthly and annual streamflow although the peak flow was over and under estimated at different hydro-gauging stations. The higher value of estimated streamflow was found at the coarsest scheme.

Impacts of climate change on urban drainage systems – a case study in Fredrikstad, Norway

Urban Water Journal, 2009

ABSTRACT Norway has frequently encountered flood damage in urban areas during recent years. In th... more ABSTRACT Norway has frequently encountered flood damage in urban areas during recent years. In this paper the authors, taking Veumdalen catchment in Fredrikstad as an example, simulated the possible consequences in the sewer system, in the present, predicted and artificial climate scenarios. Indicators that describe (1) surface flooding, (2) surcharging sewers, (3) basement flooding and (4) combined sewer overflow (CSO) are defined to represent the adverse effects of climate change. It is concluded from the annual-based simulation that the total volume of water spilling from the flooding manholes will increase 2–4-times the increase in precipitation, and the total CSO will increase 1.5–3-times as much as the increase in precipitation. The simulation results also show that the number of flooding manholes and number of surcharging sewers may change dramatically and irregularly with a slight change of precipitation, and vary with events and durations.

From Risk to Opportunity

Studies of historical large floods in Norway show that the major triggering factors of floods are... more Studies of historical large floods in Norway show that the major triggering factors of floods are rainfall and combinations of rainfall with snowmelt, avalanche or ice run. Because of its geographical location, different regions in Norway have a cold or mild climate, or both; precipitation may come alternatively as rainfall or snowfall. Most rivers have two or more flood seasons. Spring floods are the results of snowmelt, often in combination with rainfall; while autumn floods are due to intense rainfalls or storms. Because of the variation of precipitation with temperature and snowmelt water, impacts of climate change on floods are extremely sensitive in cold climates. Comparing the existing common flood risk management approach with the specific problems in the cold climate, and taking into account the emerging risk due to the dynamic changes in climate and in society and requirements for adaptation, this paper presents a comprehensive approach for flood risk management. Case stud...

The migration and accumulation of typical pollutants in the growing media layer of bioretention facilities

Environmental Science and Pollution Research

A series of complex physical and chemical processes, such as interception, migration, accumulatio... more A series of complex physical and chemical processes, such as interception, migration, accumulation, and transformation, can occur when pollutants in stormwater runoff enter the growing media layer of bioretention facilities, affecting the purification of stormwater runoff by bioretention facilities. The migration and accumulation of pollutants in the growing media layer need long-term monitoring in traditional experimental studies. In this study, we established the Hydrus-1D model of water and solution transport for the bioretention facilities. By analyzing the variation of cumulative fluxes of NO 3-N and Pb with time and depth, we investigated pollutant migration and accumulation trends in the growing media layer of bioretention facilities. It can provide support for reducing runoff pollutants in bioretention facilities. The Hydrus-1D model was calibrated and verified with experimental data, and the input data (runoff pollutant concentration) for the pollutant concentration boundary was obtained from the SWMM model. The results demonstrated that the cumulative fluxes of NO 3-N and Pb increased with the passage of simulation time and depth of the growing media layer overall. From the top to the bottom of the growing media layer, the change rates of the peak cumulative fluxes of NO 3

Flomrisiko og konsekvensanalyse : Pilotprosjekt E18 ved Hoffsbekken

Rapporten inngår i en serie rapporter fra FoUprosjektet “Klima og transport”, etatsprosjekt 2007-... more Rapporten inngår i en serie rapporter fra FoUprosjektet “Klima og transport”, etatsprosjekt 2007-2010. Hensikten med prosjektet er å forbedre rutiner og regelverk for planlegging, prosjektering, bygging, drift og vedlikehold av vegnettet som svar på endrede klimaforhold. Rapporten tilhører delprosjekt 3 ”Flom og erosjonssikring” og inneholder en hydraulisk kapasitetsberegning for en kulvert i Oslo, under E18 ved Hoffsbekken. Effekten av klimaendring og urbanisering er beregnet og kulverten vurderes som flomutsatt. Kulvertens kapasitet er ikke stor nok til en 20 års flom i Hoffsbekken

Identification and analysis of most vulnerable infrastructure in respect to floods

This document reflects only the authors' views and not those of the European Community. This work... more This document reflects only the authors' views and not those of the European Community. This work may rely on data from sources external to the members of the FloodProBE project Consortium. Members of the Consortium do not accept liability for loss or damage suffered by any third party as a result of errors or inaccuracies in such data. The information in this document is provided "as is" and no guarantee or warranty is given that the information is fit for any particular purpose. The user thereof uses the information at its sole risk and neither the European Community nor any member of the FloodProBE Consortium is liable for any use that may be made of the information.

Different hydrodynamic conditions on the deposition of organic carbon in sediment of two reservoirs

Hydrobiologia, 2015

In regulated freshwater ecosystems, the deposition process of organic carbon (OC) in sediment cou... more In regulated freshwater ecosystems, the deposition process of organic carbon (OC) in sediment could be affected by all the changes of physical, chemical, and biological factors. To assess different hydrodynamic conditions on the deposition of OC in sediment, the combination of elemental and stable isotope analyses was carried out in two reservoirs: the Huairou Reservoir (HR), which undergoes seasonal water level fluctuation (WLF) like natural lakes, and the Shisanling Reservoir (SR), which undergoes daily WLF for the operation of pumped storage power station. In general, OC concentration and its variation were comparable in the two reservoirs, whereas the OC distribution showed completely different features. The OC burial rate in SR was nearly two times more than in the HR, which reflect the impact of WLFs on the erosion of soil. For the relative contribution of phytoplankton-derived OC (P-OC), macrophytederived OC (M-OC), and terrestrial OC (T-OC) in sediment, the T-OC and M-OC in the SR were both higher than those of the HR, whereas the P-OC was markedly lower. Furthermore, the classification of nearshore and offshore sediments suggested that hydrodynamic conditions affected the T-OC import by physical processes and the in situ contributions of P-OC and M-OC with a spatial difference.

Sustainable water resources management in Tianjing, China

Sustainable Water Management Solutions for Large Cities: The Proceedings of the International Symposium on Sustainable Water Management for Large Cities (S2): Held During the Seventh Scientific Assembly of the International Association of Hydrological Sciences (IAHS) at Foz Do Iguaçu, Brazil, 3-9..., 2005

Tianjing is one of the largest cities in China. This paper provides an overview of its progress i... more Tianjing is one of the largest cities in China. This paper provides an overview of its progress in sustainable water resources management. Waterrelated problems, such as drought and flood, water pollution, deterioration of water-related ecosystem and environment, are addressed. Among them, the water shortage problem associated with the city's development is highlighted. The city's sustainable water resources development plan for the early 21st century is introduced, and the measures are described. Future ...

Editorial: Assessment and adaptation to climate change impacts in cold regions

Journal of Water and Climate Change, 2021

Evaluation of the Climate Forecast System Reanalysis Weather Data for Watershed Modeling in Upper Awash Basin, Ethiopia

Water, 2018

Availability of reliable meteorological data for watershed modeling is one of the considerable ch... more Availability of reliable meteorological data for watershed modeling is one of the considerable challenges in the Awash River Basin in Ethiopia. To overcome this challenge, the Climate Forecast System Reanalysis (CFSR) global weather data was evaluated and compared with the limited conventional weather data available in the Upper Awash Basin. The main objective of this study was to search for an optional data source for hydrological modeling, instead of using the limited available data, and for data-scarce areas of the basin. The Soil and Water Assessment Tool model was used to compare the performance of the two weather datasets at simulating monthly streamflow. For calibration, validation, and uncertainty analysis, the sequential uncertainty fitting algorithm was used. The model evaluation statistics showed that the CFSR global weather data performed similarly to the conventional weather data for simulating the observed streamflow at Melka Kunture. At Keleta, where the conventional data is scarce, the CFSR performed better. The CFSR performance at the two sub-basins indicated that it performed better for the large sub-basin, Melka Kunture. Generally, the CFSR weather data are a good addition to the dataset for areas where no reliable weather data exists for hydrological modeling in the basin. The precipitation data of the CFSR are slightly higher than that of the conventional data, which also resulted in a relatively higher water balance components.

Flomfrekvensanalyse og flomvannlinjeberegninger for byvassdrag

Utbygging og klimaendring gir raskere og større avrenning på overflater og deretter til vassdrag.... more Utbygging og klimaendring gir raskere og større avrenning på overflater og deretter til vassdrag. Dette øker flomrisikoen i vassdrag spesielt i byer. NVEs retningslinjer for planlegging og utbygging langs vassdrag forutsetter at det ikke bygges lavere enn vannivået ved 200 års flom. Denne artikkelen introduserer metoder og verktøy for å utføre flom- og flomvannlinjeberegninger i byvassdrag og hvordan dette kan gjennomføres. Flom og flomvannlinjeberegninger for Høylandsåna og Storånavassdraget i Sandnes kommune er brukt som eksempel. Det er også et mål at flom- og flomvannlinjeberegningene skal gi et grunnlag for forebyggende tiltak og til å legge inn hensynssoner langs vassdraget i forslag til ny kommunepla

China’s Sponge City Construction: Ambition and challenges

China’s Sponge City Construction (SCC) initia ted by the central government, represents an enorm... more China’s Sponge City Construction (SCC) initia ted by the central government, represents an enormous efforts and unprecedented under taking by the government for achieving urban sustainability, which presents also a global chal lenge and demand for urban planners united with implementation of natural based solutions to reduce urban flooding, water shortage and serious pollution of water courses and water bodies during urbanization and climate change. Sponge city construction aims to achieve an integrated and sustainable management of urban stormwater through its 6step approaches, i.e. Infiltration, Detention, Storage, Cleaning, Reuse and Discharge. 30 Chinese cities were selected as pilot cities, received financial support from the central government to implement of diffe rent LID solutions. This paper introduced the SCC concept, bringing together the political objectives, technical approach, guidelines, finan cial scheme, pilot projects, successful expereince, and challenges d...

Factors affecting the permeability of the growing media used in bioretention systems

Journal of Hydrology

Urban Flood Modeling of a Partially Separated and Combined Drainage System in the Grefsen Basin in Oslo, Norway

Journal of Water Management Modeling, 2022

The Storm Water Management Model (SWMM) has been globally used for stormwater management. However... more The Storm Water Management Model (SWMM) has been globally used for stormwater management. However, the calibration and evaluation of SWMM for historical rainfall–runoff events in partially separated and combined drainage systems is rarely reported in Norway. In this study, we employed SWMM for the Grefsen catchment in Oslo, Norway. The main problem in the Grefsen basin is combined sewer overflow. We calibrated the model parameters based on 32 rainfall–runoff events and evaluated the calibrations using four indicators: Nash–Sutcliffe efficiency, percentage bias, and continuity errors for runoff and flow. There were 32 successful calibrations using Nash–Sutcliffe efficiency, 30 successful calibrations using percentage bias, 32 successful calibrations using continuity error runoff, and four successful calibrations using continuity error flow. SWMM can well simulate the dynamics of hydrological and hydraulic systems in this catchment. Among the 124 validations, there were 88 successful ...

Enrichment Evaluation of Heavy Metals from Stormwater Runoff to Soil and Shrubs in Bioretention Facilities

Water, 2022

Bioretention facilities with different inflow concentrations, growing media and plants were exami... more Bioretention facilities with different inflow concentrations, growing media and plants were examined to determine whether the soil in these facilities was polluted with heavy metals and whether runoff had obvious toxic effects on plants. Using Beijing soil background value as the standard, the soils were evaluated by bioaccumulation index and single factor index. The results show that stormwater runoff containing Cu caused slight pollution in soils, and stormwater runoff containing Zn and Pb was not polluted. Nemerow comprehensive index evaluation revealed that the heavy metals content in the facilities containing vermiculite (a yellow or brown mineral found as an alteration product of mica and other minerals, used for insulation or as a moisture-retentive medium for growing plants) and perlite (a form of obsidian characterized by spherulites formed by cracking of the volcanic glass during cooling, used as insulation or in plant growth media) were higher than the standard. High infl...

Factors affecting the ability of extensive green roofs to reduce nutrient pollutants in rainfall runoff

Science of The Total Environment, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Assessment of the impacts of landscape patterns on water quality in Trondheim rivers and Fjord, Norway

Water Supply

Due to the impacts of hydrological and ecological processes on water quality, discharges from ups... more Due to the impacts of hydrological and ecological processes on water quality, discharges from upstream catchments have induced significant pollution to the recipients. This study aims to investigate the possible pollution sources from catchments with different types of land use and landscape patterns and develop the relationships between water quality and the catchment hydro-geological and environmental variables. Data from 10 monitoring sites in Trondheim formulated the basis of the case study. Thermotolerant coliform bacteria (TCB) and total phosphorus (TP) were applied as main indicators to represent the water quality in the recipient rivers, streams and in Trondheim Fjord. Based on the GIS-oriented spatial analysis, 15 hydro-geographical and landscape parameters were selected as explanatory variables. Multiple linear regression (MLR) models were developed at catchment and river reach scales to study correlations between the explanatory variables and the response variables, TCB a...

A Review of Hydrological Models Applied in the Permafrost-Dominated Arctic Region

Geosciences, 2020

The Arctic region is the most sensitive region to climate change. Hydrological models are fundame... more The Arctic region is the most sensitive region to climate change. Hydrological models are fundamental tools for climate change impact assessment. However, due to the extreme weather conditions, specific hydrological process, and data acquisition challenges in the Arctic, it is crucial to select suitable hydrological model(s) for this region. In this paper, a comprehensive review and comparison of different models is conducted based on recently available studies. The functionality, limitations, and suitability of the potential hydrological models for the Arctic hydrological process are analyzed, including: (1) The surface hydrological models Topoflow, DMHS (deterministic modeling hydrological system), HBV (Hydrologiska Byråns Vattenbalansavdelning), SWAT (soil and water assessment tool), WaSiM (water balance simulation model), ECOMAG (ecological model for applied geophysics), and CRHM (cold regions hydrological model); and (2) the cryo-hydrogeological models ATS (arctic terrestrial s...

Quantifying the effects of watershed subdivision scale and spatial density of weather inputs on hydrological simulations in a Norwegian Arctic watershed

Journal of Water and Climate Change, 2021

The effects of watershed subdivisions on hydrological simulations have not been evaluated in Arct... more The effects of watershed subdivisions on hydrological simulations have not been evaluated in Arctic conditions yet. This study applied the Soil and Water Assessment Tool and the threshold drainage area (TDA) technique to evaluate the impacts of watershed subdivision on hydrological simulations at a 5,913-km2 Arctic watershed, Målselv. The watershed was discretized according to four TDA scheme scales including 200, 2,000, 5,000, and 10,000 ha. The impacts of different TDA schemes on hydrological simulations in water balance components, snowmelt runoff, and streamflow were investigated. The study revealed that the complexity of terrain and topographic attributes altered significantly in the coarse discretizations: (1) total stream length (−47.2 to −74.6%); (2) average stream slope (−68 to −83%); and (3) drainage density (−24.2 to −51.5%). The spatial density of weather grid integration reduced from −5 to −33.33% in the coarse schemes. The annual mean potential evapotranspiration, evap...

Sensitivity analysis of the SWAT model to spatial distribution of precipitation in streamflow simulation in an Arctic watershed

IOP Conference Series: Earth and Environmental Science, 2020

This study approached a physically based, semi-distributed SWAT model to test the model sensitivi... more This study approached a physically based, semi-distributed SWAT model to test the model sensitivity to the spatial distribution of precipitation. Ten scenarios of precipitation from five scattered rain gauges in an Arctic watershed Målselv in northern Norway were used as inputs to run the SWAT model. Streamflows were simulated. The model runs at monthly time interval based on the historical data of precipitation from 1979-2012. The study used statistical parameters, values of long-term average monthly streamflow and streamflow hydrograph between simulated and observed data for sensitivity analysis. The study found that the result of streamflow simulation is highly sensitive with spatial distribution of rain gauges input. For instance, the scenarios integrating rain gauge number 3, locating inside the watershed with lower precipitation amount than average of selected rain gauges, provided model unsatisfactory (statistical coefficient NSE < 0.5) in streamflow simulation. However, s...

Evaluating the Effects of Watershed Subdivision on Hydrological Simulation by Swat Model in an Arctic Watershed

IOP Conference Series: Earth and Environmental Science, 2020

The hydrological model SWAT is a state-of-the-art tool for environmental and water resources mana... more The hydrological model SWAT is a state-of-the-art tool for environmental and water resources management. Like other semi-distributed models, the whole river basin in the SWAT model is delineated into smaller sub-basins prior to conducting the simulation. Watershed delineation is an importance step since it could potentially influence the modelling results. The present study aimed to conducte an investigation of the effects of watershed delineation schemes on hydrological simulation in an Arctic watershed Målselv, north of Norway. Four delineation schemes were set up with different threshold drainage area (TDA) from fine to coarse including 100 ha, 2,000 ha, 5,000 ha and 10,000 ha. The model was run on monthly time step from 1979-2012. The results showed higher variation of average annual precipitation and runoff especially in the upstream sections of the watershed by the fine TDA schemes compared to the coarse ones. The average monthly precipitation and runoff slightly increased from the finest TDA scheme to the coarsest scheme. All TDA schemes reproduced the observed tendency of the average monthly and annual streamflow although the peak flow was over and under estimated at different hydro-gauging stations. The higher value of estimated streamflow was found at the coarsest scheme.

Impacts of climate change on urban drainage systems – a case study in Fredrikstad, Norway

Urban Water Journal, 2009

ABSTRACT Norway has frequently encountered flood damage in urban areas during recent years. In th... more ABSTRACT Norway has frequently encountered flood damage in urban areas during recent years. In this paper the authors, taking Veumdalen catchment in Fredrikstad as an example, simulated the possible consequences in the sewer system, in the present, predicted and artificial climate scenarios. Indicators that describe (1) surface flooding, (2) surcharging sewers, (3) basement flooding and (4) combined sewer overflow (CSO) are defined to represent the adverse effects of climate change. It is concluded from the annual-based simulation that the total volume of water spilling from the flooding manholes will increase 2–4-times the increase in precipitation, and the total CSO will increase 1.5–3-times as much as the increase in precipitation. The simulation results also show that the number of flooding manholes and number of surcharging sewers may change dramatically and irregularly with a slight change of precipitation, and vary with events and durations.

From Risk to Opportunity

Studies of historical large floods in Norway show that the major triggering factors of floods are... more Studies of historical large floods in Norway show that the major triggering factors of floods are rainfall and combinations of rainfall with snowmelt, avalanche or ice run. Because of its geographical location, different regions in Norway have a cold or mild climate, or both; precipitation may come alternatively as rainfall or snowfall. Most rivers have two or more flood seasons. Spring floods are the results of snowmelt, often in combination with rainfall; while autumn floods are due to intense rainfalls or storms. Because of the variation of precipitation with temperature and snowmelt water, impacts of climate change on floods are extremely sensitive in cold climates. Comparing the existing common flood risk management approach with the specific problems in the cold climate, and taking into account the emerging risk due to the dynamic changes in climate and in society and requirements for adaptation, this paper presents a comprehensive approach for flood risk management. Case stud...